Joe Palca

Joe Palca is a science correspondent for NPR. Since joining NPR in 1992, Palca has covered a range of science topics — everything from biomedical research to astronomy. He is currently focused on the eponymous series, "Joe's Big Idea." Stories in the series explore the minds and motivations of scientists and inventors.

Palca began his journalism career in television in 1982, working as a health producer for the CBS affiliate in Washington, DC. In 1986, he left television for a seven-year stint as a print journalist, first as the Washington news editor for Nature, and then as a senior correspondent for Science Magazine.

In October 2009, Palca took a six-month leave from NPR to become science writer in residence at the Huntington Library and The Huntington Library, Art Collections, and Botanical Gardens.

Palca has won numerous awards, including the National Academies Communications Award, the Science-in-Society Award of the National Association of Science Writers, the American Chemical Society James T. Grady-James H. Stack Award for Interpreting Chemistry for the Public, the American Association for the Advancement of Science Journalism Prize, and the Victor Cohn Prize for Excellence in Medical Writing.

An Italian team of scientists says it has strong evidence of a subsurface lake of liquid water on Mars. It's a discovery that adds to the speculation that there could once have been life on Mars — and raises the possibility that it might be there still today, since liquid water is an essential ingredient for life.

When people think of particle accelerators, they tend to think of giant structures: tunnels many miles long that electrons and protons race through at tremendous speeds, packing enormous energy.

But scientists in California think small is beautiful. They want to build an accelerator on semiconductor chips. An accelerator built that way won't achieve the energy of its much larger cousins, but it could accelerate material research and revolutionize medical therapy.

More than 400 years after Galileo Galilei discovered the first of Jupiter's moons, astronomers have found a dozen more — including one they've dubbed "oddball" — orbiting the planet. That brings the total number of Jovian moons to 79.

Scientists for the first time have been able to pinpoint the source of an extremely powerful version of a neutrino, a ghostly particle that can travel virtually unimpeded through space.

It's an achievement that opens a whole new way of looking at the universe.

The neutrino was detected by a South Pole observatory called IceCube that was specifically designed to catch the particles. It consists of a cubic kilometer of ice festooned with more than 5,000 detectors.

A giant dust storm on Mars is threatening to end the mission of a NASA rover. The rover called Opportunity depends on solar panels to charge its batteries. Right now, the storm has practically blotted out the sun. NPR's Joe Palca has more.

Each year, malaria kills about half a million people around the world. Health officials say a fast, cheap, accurate way to test for people infected with the malaria parasite would be extremely helpful in combating the disease. Now some engineers in California say they've invented a device they hope someday will do just that.

The device takes advantage of the fact that the malaria parasite produces tiny crystals inside infected red blood cells. These crystals have a magnetic property. Put a magnet next to a drop of infected blood, and the crystals move toward the magnet.

Scientists have new evidence that there are plumes of water erupting from the surface of Jupiter's icy moon Europa — plumes that could, maybe, possibly contain signs of life.

The evidence comes from data collected by the now-defunct Galileo spacecraft. Although the data has been available since it was collected in 1997, it's only now that an analysis confirms the existence of water plumes.

NASA is heading back to Mars. If all goes well, a two-stage Atlas V 401 will lift off from California's Vandenberg Air Force Base on Saturday morning. Onboard will be a lander named InSight, an $813.8 million mission to study the interior of the Red Planet.

Recent Mars missions have snapped pictures of the surface, studied rocks, dug in the dirt and looked for signs that water once flowed on Mars. But as Insight's principal investigator William "Bruce" Banerdt sees it, that's just scratching the surface.

An engineer in California has an invention that she hopes will someday help people with damaged lungs breathe easier.

Stanford University's Annelise Baron has developed a synthetic version of something called lung surfactant. Lung surfactant coats the tiny air sacs in the lung. Without it, every breath would be a struggle, like blowing up millions of little balloons. With surfactant, breathing is as easy as blowing soap bubbles.

A critical part of NASA's next $2 billion rover mission to Mars broke during testing earlier this month.

The Mars 2020 mission's heat shield was undergoing stress-testing when it developed a crack that appeared around its entire circumference. The shield is designed to protect the rover as it enters the Martian atmosphere.

A startup company in California is using machine learning and artificial intelligence to advise fire departments about how to plan for earthquakes and respond to them.

The company, One Concern, hopes its algorithms can take a lot of the guesswork out of the planning process for disaster response by making accurate predictions about earthquake damage. It's one of a handful of companies rolling out artificial intelligence and machine learning systems that could help predict and respond to floods, cyber-attacks and other large-scale disasters.

Nothing conveys the excitement of space exploration like pictures from another planet. Now NASA is planning to go one better than pictures. The space agency is aiming to launch a probe carrying a communication system that will let future missions to Mars transmit live, high definition video to Earth.

Astronomers in California are building the largest digital camera in the world. It will go on a giant telescope taking shape in Chile called the Large Synoptic Survey Telescope.

LSST is different from most large telescopes. Instead of staring at a tiny patch of the sky and taking essentially one snapshot in time, LSST will take a panorama of every part of the sky...and it will do so over and over and over. The idea is to see what's moving or changing in the heavens.

Editor's note: The Environmental Protection Agency has approved the use of mosquitoes infected with Wolbachia bacteria as a "biopesticide" in 20 states and the District of Columbia. The bacteria keep mosquitoes from spreading diseases like dengue and Zika. Back in 2012, NPR's Joe Palca wrote about scientist Scott O'Neill's 20 years of struggle to make the idea of Wolbachia-infected mosquitoes work. Here is his story.

Scientists in California think they may have found a way to transplant insulin-producing cells into diabetic patients who lack those cells — and protect the little insulin-producers from immune rejection. Their system, one of several promising approaches under development, hasn't yet been tested in people. But if it works, it could make living with diabetes much less of a burden.

For now, patients with Type-1 diabetes have to regularly test their blood sugar levels, and inject themselves with insulin when it's needed.

After 13 years in orbit around Saturn, NASA's Cassini spacecraft is about to plunge itself into the planet's atmosphere and disintegrate. NASA decided to put an end to the mission on Friday because the probe is almost out of fuel.

Cassini has provided exquisite details about the second-largest planet in our solar system.

When you want to change the world, a good invention helps. But that is just the start.

Take the story of Mike Davidson and Mike Smith: They wanted to change the world of dental hygiene with a new kind of toothbrush.

Three years ago, their brushes were rolling off the assembly line, ready for consumers. But then the pair ran into a business buzz saw, and it changed the way they saw the business of invention forever.